Fig. 39. Cidaris papillata Leske. The pyramid 5 witli its muscles, from 

 above, showiug the upper surface of tlie epiphyses, the compass, and 

 the m. radiales. On the auricular hranch a the m. protractor and 

 m. retractor are both preserved; on the b the m. re. is exposed, the 

 m. pro. being removed. 



Fig. 4U. Thi" peristomal part of the interradium 5, seen from the stoma. On 

 b both muscles are cut away, their attachments left. On a both 

 muscles are in situ, entire, with their lines of insertion in the sub- 

 marginal groove of the pyramid. 



Fig. 41. Tlu' pyramid 5 from without, the auricular l)ranches being removed. 

 On tlie (i the ni. pro. is entire, tlie m. re. is removed save its in- 

 sertion; on the b the insertion ouly is left of the m. pro., while the 

 m. re. is entire. 



Fig. 42. The half-pyramid "i o, side-view. The m. re. and m. pro. both in 

 situ. The articulatiou of the epiphysis: the glenoidal fossa, gl., for 

 the condyloid prominence, cond. fig. 44; the interiör and exteriör 

 tubercles tu. i., tu. e, for the fo. i. and fo. c, and the rotular mus- 

 cles, m. rot. i. and m. rot. e. 



Fig. 43. The half-pyramid 5 a from the side. both muscles in situ, the ten- 

 dinous part of the m. re. in view. 



Fig. 44. A rotula from the under side, tlie inner end in front; letters as in 

 fig. 42. 



Fig. 45. Section of rotula and epiphysis with m. ro. i. 



Fig. 46. Section of the same with vi. ro e. 



Fig. 47. Echinomctra Lucunter L. The dental apparatus seen from the 

 interradium 5. The broad and linear protractors arising from it, 

 the retractors from auricular liranches I o and V b. 



Fig. 48. The motor muscles seen from the interiör, the pyramids being ro- 

 nioved; the m. 2^'>'0. entire. showing their insertion on the upper part 

 of the pyramid T); the two in. re. of the 5 from I a and V b; the 

 re I b removed, the V a, belonging to the pyramid 4 b, entire. 



Fig. 49. The epiphysis with the articulatiou and the m. rotulares. 



Fig. fiO. Asthenosoma varium Grube. The dental apparatus seen from the 

 interiör. The tender auricles, which give attachment to the retrac- 

 tors, supported by the flexible ambulacrum, are stayed by means of 

 muscles from the »longitudinal muscles», and others from the buccal 

 membrane. 



Fig. 51. The epiphysis. with the articulatiou and the m. rotulares. 



